They will also make cocoons all winter which will all hatch in early spring. This will make a big difference to the speed of composting when spring arrives and you get a huge burst of hungry young worms in the compost.
How they work: like a conventional Duvet in that any heat below causes the stuffing to swell up and provide a physical barrier preventing the natural heat from escaping. This concept has proved to maintain high temperatures within the compost, both day and night. This heat can be maintained for up to 10 days. It will also keep out frosts in winter so that the worms can work all year round. The Duvet fits snugly into the wooden bins but it can be used on any compost pile.